Morphological characterization of the mouthparts of the vector leafhopper Psammotettix striatus (L.) (Hemiptera: Cicadellidae).

The leafhopper Psammotettix striatus (L.) (Hemiptera: Cicadellidae), is one of the most significant economic pests of wheat in Western China. This insect vectors a phytoplasma that causes wheat blue dwarf (WBD), a severe disease limiting wheat production in the Western China. A microscopic analysis of the ultrastructure of the mouthparts of the adult was conducted using scanning electron microscopy and the putative functions of the mouthparts were determined. The piercing-sucking mouthparts of P. striatus are of the conventional type comprising a three-segmented labium with a deep groove in the anterior side, a stylet fascicle consisting of two mandibular and two maxillary stylets, and an uppermost small cone-shaped labrum. The mandibular stylets, located laterad of the maxillary stylets, have sculpture on their tips, which may function in tearing plant tissue, cutting channels into the plant tissues, and attaching the body to the host plant during molting. The maxillary stylets are interlocked to form two separate compartments, a larger food canal and a smaller salivary canal. Two dendritic canals are also found in each maxilla and one in each mandible. Four kinds of sensilla were found on the labium: s. trichodea I, s. trichodea II, s. basiconic I, s. basiconic II. These may be involved in host recognition and are likely chemo- or mechanosensory, or both.